Machine for overcast sewing



Aug 27, 1968 A. DE KONINCK 3,398,709

MACHINE FOR OVERCAST SEWING Filed Sept. l1, 1964 6 Sheets-Sheet l Aug. 27, 1968 A. DE KONINCK 3,398,709

MACHINE FOR OVERCAST SEWING Filed Sept. ll, 1964 6 Sheets-Sheet 2 i l l 5 60 i *iV 43 im 5in tlli i; 'y

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Aug- 27, 1968 A. DE KoNlNcK 3,398,709

MACHINE FOR OVERCAST SEWING Filed sept. 11I 1964 e sheets-sheet 75 ,f/ p77 l 6 74 8O I ii l Il l I 7 1 1% i 1J 1 I ug. 27, 1968 A. DE KONINCK 3,398,709

MACHINE FOR OVERCAST SEWING Filed Sept. 11, 1964 6 Sheets-Shea?l 4 /NVEA/TOR By ALPHONSE DE KONINCK ATT EYS Aug. 27, 1968 A. DE KONINCK 3,398,709

MACHINE PoR ovERCAsT SEWING Filed Sept. 11, 1964 6 Sheets-Sheet 5 FIG. 10.

Upper position of the hook 3 D\ ,A B C D' Lower posltlon of the hook 3 /NVENTOR y ALPHONSE DE KON NCK www @1go/M TURA/EVS Allg 27, 1968 A. DE KoNlNcK 3,398,709

MACHINE FOR OVERCAST SEWING Filed Sept. l1, 1964 G Sheets-Sheet G FIG. 11

v INVENTOR ALPHONSE DE KON l NCK 3,398,709 Patented Aug. 27, 1968 11 claims. (cl. 112-162) ABSTRACT OF THE DISCLOSURE A machine for overcast sewing having a straight needle and two hooks, at least one of which can be threaded. The needle and hooks are driven by a crankshaft via connecting rods, both the rods and crankshaft being disposed in a gearcase. A feed dog and knife means are operatively connected to be driven by the crankshaft. A pressing pedal, thread guides, thread distributors and a reciprocating needle bar are also mounted on the gearcase. The case has an integral bushing with the bar sliding therein so that, when the needle is in its lower position, a greater portion of the bar is within the gearcase to be lubricated by aspersion of oil contained in the gearcase.

This invention refers to a machine for overcast sewing, particularly for the sewing of bags, in the carpet industry for the overcast stitch, and the like, including a straight needle and two hooks at least one of which can be threaded. Both the needle and the hooks are actuated by connecting rods from a crankshaft driven by a motor. The connecting rods and the crankshaft are arranged in a gearcase. The crankshaft also controls a feed dog and a knife for the cutting of the edge of objects to be overcast. A pressing pedal as well as thread guides and thread distributors are included in said machine.

Existing machines for overcast sewing, used in the manufacture of bags and in the carpet industry, present several drawbacks. In fact, in the existing machines, the needle bar is diicult to lubricate. Lubrication oil distributed by a wick or tank on the upper part of the needle bar runs quickly along the needle and soils the objects being overcast. These machines have a low rotational speed and their mechanism is encased in a gearcase into which scraps of material can penetrate when the machine is in use. These scraps cause the early wearing out of the mechanical parts of the machine. Known machines also present the drawback of not allowing the making of overcast stitches on objects presenting a non-linear outline and particularly on objects presenting inner cuttings of a slight curve.

In an attempt to obviate the difficulty in lubrication of the needle bars, machines have been built using an axlemounted curved needle. These machines, used in the underwear industry, can only be used to overcast material offering very little resistance to the needle penetration. A slight increase of this resistance causes a variation in the curve radius of the needle which will break against a hook or stationary part of the machine. The fragility of the curved needles is such that it is rather diicult in the underwear industry to assemble parts including a rubber band.

The object of this invention is to remedy these drawbacks and to provide a machine having a high rotational speed capable of making overcast stitches on objects of slight thickness and offering little resistance to the needle penetration, as is the case in the underwear industry. This inventive machine is also capable of making overcast stitches on objects of great thickness and offering a high resistance to the needle penetration, for instance in the carpet industry. These overcast stitches are also possible on objects presenting any outline. All the mobile parts of the machine are encased in a tight gearcase which is constantly lubricated by oil aspersion from the gearcase.

To this end, according to the invention, the needle is flag mounted on a needle bar having an alternate travel motion. The bar slides in a bushing, integral with the gearcase, so that, when the needle is in lower position, a greater portion of the bar is positioned within said gearcase where it is lubricated by aspersion of the oil inside the gearcase.

According to an advantageous embodiment of the invention, the threaded hook is set on a hook bar sliding in a swivel socketed in an element xed to the gearcase. This element has openings to allow for the passage and motions of the hook bar. The latter being actuated with an alternate travel motion in the above-mentioned swivel. The set of connecting rods controlling the hook bar are disposed in such a way that, by acting on the bar and during its travel, they will make the swivel to rotate with the longitudinal axis of the hook bar constantly moving in a same plane. The second hook of the machine is actuated with a rotary motion around an axle mounted in the gearcase.

According to an advantageous embodiment of the invention, the second hook of the machine is mounted on a stand xed to an axle set in a bearing inside the gearcase and controlled by a lever. An oscillating lever, controlled by said crankshaft, is linked to the lever -by a small connecting rod, the length of which and its articulation points, with respect to the lever and to the oscillating lever, are so chosen that the second hook will remain stationary, in lower position, during part of the oscillating lever travel. The hook will have an accelerated rotary motion to reach its upper position and then have a slow rotary motion to allow the hook to regain its lower position.

According to a particularly advantageous embodiment of this invention, the mechanism of the pressing pedal and the stationary part of the aforesaid knife are tted to the gearcase by a stand, of small section, located near the aforesaid needle bar. The gearcase presents a completely open working surface. The position of the needle bar and the stand allows the overcasting of objects with any outline and particularly of objects with inner cuttings of a slight curve.

According to an embodiment of the invention, the movements of the machine feed dog and of the mobile part of the yknife are controlled from a single eccentric, mounted on the aforesaid crankshaft, in order to make their related motions invariable.

The bar bearing the mobile part of the knife slides in a bushing integral with the gearcase to become lubricated by aspersion of the -gearcase oil and in such a way that the cutting takes place while said bar moves upwards, so that the cut part of the object to be overcast is moved upwardly.

Other details and particularities of this invention will become apparent from the description of the drawings annexed to the present specification and which show, as a non limitative example, an embodiment of this invention.

FIGURE 1 is an elevation view of the machine, with parts broken away.

FIGURE 2 is an elevation view, with parts broken away, showing the crankshaft of the machine and the pressing pedal arrangement.

FIGURE 3 is a cross-section view along line III-III of FIGURE 1, showing the needle driving mechanism.

FIGURE 4 is a cross-section view of the machine, showing the controls of the clip and of the bar bearing the mobile part of the knife.

FIGURE 5 is a sectional view along line V-V of FIGURE l.

FIGURE 6 is a partial end view of the machine, showing the thread distributor of the threaded hook.

FIGS. 7 and 8 are enlarged partial views of a part of the machine of FIGURE 1 illustrating different positions of the hooks.

FIG. 9 is a diagram of different relative positions of the conveying hook and of the rods connected thereto, both being represented by axes thereof.

FIG. 10 is a diagram of the position of the conveying hook in relation to the time, `for a cycle of oscillating motion of the lever 31.

FIG. l1 is a top plan view of the inventive machine.

In the various tigures, the same reference numerals pertain to like elements.

The machine according to the invention is powered by a motor which is not shown. The motor drives the crankshaft 4 which controls, through levers and connecting rods, the needle 1, the threaded hook 2 and the conveying hook 3.

Needle 1 is flag mounted on the needle bar 13. Needle bar 13 is mounted in such a way that it can slide in a bushing 14', which is integral with gearcase 70 of the machine (FIGURE 3). Needle bar 13 is driven from part of crank-shaft 4 by a connecting rod 10 acting, through swivel 6, on an oscillating lever 11. The lever is mounted on shaft 7 which rotates in bearings integral with gearcase 70. The lever 11 carrying at one end an axle 8 linked by a little connecting rod 12 to an axle 9 integral with the needle bar. Axle 9, fixed by one of its ends to the needle bar, bears at its other end, a roller 21' running in a slideway 22' provided in the gearcase of the machine (FIGURE 1). The needle bar is actuated with a reciprocating translation motion, roller 21' together with slideway 22' preventing any rotation of said bar around its longitudinal axis. The foot of rod is tted on a swivel 15 linked to crankshaft 4 by a needle bearing 14. The use of needle bearings in the assembling of the rod feet on crankshaft 4, or in `the setting of other machine parts allows a considerable increase in the rotational speed of the machine, while reducing wear to a minimum.

Threaded hook 2 is set on a hook bar 22. This hook bar 22 slides inside a swivel 23, set in an element 24 introduced in a cut 25 of gearcase 70, and is held in place by pressure screws, which are not shown (FIGURE 1). The hook motion is controlled from crankshaft 4 through a rod 16. This rod controls a swivel 17, integral with a shank 18, carried by an element 19 set on shaft 20. Shaft 20 oscillates in bearings integral with gearcase 70 and controls a lever 21, the opposite end of which is coupled the hook bar 22. During the reciprocating translation motion of bar 22, swivel 23 is given, by lever 21 and bar 22, a rotary motion around an axis 26 perpendicular to the drawing plane (FIGURE 1). The combined motion of rod 22 and swivel 23 allows, on the one hand, when hook 2 is at its upstroke position, an upward tilting .of the hook which places it in the way of the conveying hook 3 at a higher level to shorten the effective stroke of the conveying hook 3 and, on the other hand, when hook 2 ends its downstroke, it holds the thread or threads, which are threaded thereon, substantially against the object to be overcast, so that only a short needle travel will fix these threads on said object.

This manner of operation allows, on the one hand, shortening of the elbow of hook 3, thus ensuring a higher machine speed and, on the other hand, obtaining an overcast object with overcasting threads well stretched on the edge and covering the latter on both sides of said object over substantially equal distances.

Conveying hook 3 is given a rotary motion by an axle 36 on which it is set by means of a bearing 35 and screw 38' which makes hook 3 integral with bearing 35. The position of axle 36 and the curvatures of the hook 3 allow, in the bag manufacture or in the carpet industry, the making of overcast stitches at a rather large distance from the carpet or bag edge(s). Axle 36, which bears hook 3, rotates in a bushing 38 integral with gearcase and is controlled from crank-shaft 4 (FIGURE l) through a rod 26' acting on a swivel 27 set on axle 28. The latter is integral with an arm 29 carried by a bushing 30 which turns freely around aXle 20 and carries an elbowed lever 31. The elbowed lever 31 has an oscillating motion and is linked, through articulated axles 33 and 33', by a small connecting rod 32 to a lever 34 which is integral with axle 36. The length of the small connecting rod 32 and its articulation points 33- and 33', with respect to the elbowed lever 31 and to lever 34, are so chosen that hook 3 remains stationary in its lower position during the high portion of the upward and downward travel of the elbowed lever 31. In order for hook 3 to regain its upper position it is given an accelerated rotary motion and returns afterward to its lower position through a slacken rotary motion. This method of driving hook 3, combined with the method of driving the threaded hook 2 enables considerable reduction in the strokes of needle 1 and of hooks 2 and 3, thus considerably increasing the machine speed.

The relative positions of needle 1 and hooks 2 and 3 are shown in more detail in FIGURES 7 to 10.

In FIGURE 7 the full lines show the respective positions of the hooks at the moment the threaded hook 2 presents its thread to the conveying hook 3 which is rotating upwards; the dotted lines show hook 3 in two other positions, first in its highest position 3 to cooperate with needle 2 to form a stitch and secondly in its lowest position 3.

In FIGURE 8 the full lines show the respective positions of the hooks 2 and 3, the conveying hook being in its highest position 3', while hook 2 moves Ifrom its highest position 2 back to its lowest position 2", beneath the work support 81' (these two last positions are represented in dotted lines). Hook 2 has thus a reciprocating movement through the swivel 23 which enables its threaded end to move close to the work support 81 in the vicintiy of the needle 1, while said end is given a substantial upwards movement when it reaches the position where it cooperates with the conveying hook 3. This movement of the threaded end of hook 2 enables shortening the needle stroke beneath the work support 81' and also shortening the conveying hook 3 stroke beneath the work support 81'; this shortens the time to make a stitch and thus makes possible a greater machine speed.

In FIGURE 9 lever 31, rod 32, lever 34 and hook 3 are represented by their axes in four different positions. Reading FIGURE 9 and FIGURE 10 together, if we consider that position 31', 32', 34 and 3' is the starting position of the elements from the upper position of the hook (D), we see that to position 31", 32", 34", the hook 3 goes down (A). During the movement of 31, 32 between positions 31" and 31'", (B), the lever 34 remains substantially stationary (in fact, it goes a very little down) and the hook 3 also remains substantially stationary (in fact, it goes a little upwards). When lever 31 begins its downwards stroke, the first part of this movement (to C) produces no substantial movement of the hook (in fact, a very slight downwards movement of the hook 3 which returns to its lower position); the following part of the downwards movement of the lever 31 produces the upwards movement of the hook 3 to position D.

From the above explanation, it will be understood that if we consider the area of time AC, the movement of the hook 3 has no effect upon the making of a stitch; the advantages of the arrangement described are that the stroke of the hook 3 is shortened in relation to the stroke of the lever 31 which shortens the time necessary for this hook to regain its upper position while giving a time (corresponding to the last part of the upwards stroke and the rst part of the downwards stroke of the lever 31) for free cooperation between those stitch-forming elements (needle 1 and hook 2) which have to coact without intervention of the hook 3.

Motions of feed dog 41 and knife 42 of the machine are obtained from crank-shaft 4 by an eccentric 40 acting on an element 43. The eccentric 40 is fixed on the crankshaft and drives element 43 through a swivel and a needle bearing. Feed dog 41 is mounted on a feed dog-bearing bar 50 which can slide in said element 43. The purpose of swivel element 53 is to raise and lower bar 50 while ensuring its guiding, the bar being further driven by a mechanism 51 ensuring the transversal displacement of bar 50 in relation with crankshaft 4. Mechanism 51 is driven by an eccentric 47, set `on crankshaft 4, acting on levers 70 and 71', which are articulated in 72', and driving an axle 45, mounted on bearings integral with gearcase 70 o n which is iitted a lever 44 acting, through axle 46, on a lever 52 carrying the feed dog-bearing bar. The clip-bearing bar 50 runs through swivel element 53 set in a bushing 54 which can move, following arrows 71', in a housing 55 in the gearcase. The mobile part of knife 42' is driven from the crankshaft 4 through the element 43 and a lever 56 fitted in a bushing 57, the latter turning freely around said axle 7. Lever 56 presents a forked end 58 acting on an element 59 turning around axle 59 and held between two side-plates of a part 60' on which is mounted the knife-bearing bar 61 which slides in a bushing 61'. Motions of vfeed dog 41 and of mobile part of knife 42' result from being driven by the same source, i.e. eccentric 40, their relative motions being invariable. The machine according to the invention has the advantage of presenting a knife the mobile part of which acts upwards; this knife feature enables, when operating with stiff materials, the upward deviation of the cut material so that the working table remains free.

The support 71 of the mechanism of the pressing pedal 72 and of the knife stationary part 42 is of thin section and located near the needle bar 13. The result of the disposition of the various mechanisms is a gearcase presenting a level working bar, the disposition of the su-pport 71 and the needle bar 13 enables the machine, according to the invention, to overcast stitches on objects with any youtline and particularly to overcast stitches on objects having inner cuttings of slight curve. All the machine mobile parts are constantly lubricated by oil aspersion from gearcase 70, the latter being tight. Tightness of gearcase 70 is obtained thanks to the good lubrication of needle bar and knife-bearing bar; these, being well lubricated, wear out very little and the play between the above mentioned bars and the bushings 14 and 61' does not permit the draining from the oil of the gearcase. This tightness is also obtained through the setting up of hook bar 22 and feed dog-bearing bar 50. The gearcase tightness ensures the machine, according to the invention, great advantages as the objects being worked cannot be soiled, the scraps cannot any longer reach the parts in motion rotating at high speed, and the machine can be moved without any oil spilling.

The machine according to the invtntion also includes a distributor 74 of thread -for hook 2. Distributor 74 consists of a U-section sector tixed in an adjustable manner, by liange 75 of sector U to gearcase 70 of the machine. Each flange 75 and 76 of the U-section sector has a hole 77 through which the thread or threads of the hook 2 pass. A lever 78, set on axle 7 driven by crankshaft 4, has a constant alternating rotary motion between the sector anges 75 and 76 to pull through said holes the desired length of thread, the end 79 of this lever passing through an opening 80 made at the foot of said U to avoid the getting away of the threads from the lever. The length of distributed thread is determined by the position of said holes in relation to themachine gearcase 70.

It is understood that the invention is in no way limited to the embodiment described and that many modifications can be brought to it without departing from the scope of the present patent.

For instance, the machine according to the invention may be used with two threaded hooks.

I claim:

1. In a sewing machine of the overedge stitching type, a closed, hollow box-like case containing lubricating oil; a flat horizontal work support surmounting said case, an oil-tight bearing in the surface of said fiat horizontal work support, a longitudinally reciprocating needle bar extending from within the case through said oil-tight bearing; a needle carried by the part of the bar outside the case; a hook bar; a threaded hook mounted on one end of said hook bar to cooperate with the needle beneath the 'work support; a swivel set in the case, said hook bar reciprocating in said swivel; a curved hook; oscillating means for oscillating said curved hook, said curved hook having a trajectory which enables it to cooperate, in a low position, with said lirst mentioned threaded hook and, in a high position, with said needle; a rotatably driven crank-shaft extending longitudinally within said case; connecting means operatively connecting said crank vshaft within said case to said needle bar for reciprocating Said needle bar, to said hook bar for reciprocating said first-mentioned hook and to said oscillating means for oscillating said curved hook, all in coordinated relation to form said overedge stitching.

2. A sewing machine according to claim 1, further comprising an element fixed to said gearcase, said swivel set in said element, said hook bar carrying said threaded hook thereon slidingly mounted in said swivel; means for imparting a reciprocating motion to said hook bar in said swivel, said means for driving the hook bar being further arranged to make the swivel rotate by acting on the bar during its travel, said rotation being very slight during the movement of the threaded hook beneath the work support and more rapid during the other part of the movement where the threaded hook cooperates with the curved hook, said more rapid rotation resulting in a relatively rapid lift of the threaded end of the threaded hook.

3. A sewing machine according to claim 1 further comprising a pivoting axle, said curved hook being fixed to said axle, said means for oscillating said curved hook comprising a main oscillating lever driven by said crank shaft, said oscillating lever being adapted to oscillate between an upper and a lower position, a lever adapted to oscillate between an upper and a lower position, a lever attached to said axle and a rod connecting said main oscillating lever and said lever, the length of the connecting rod being such that the curved hook remains substantially stationary in the lower position thereof` during the last part of the upward and the first part of the downward travel of the main oscillating lever.

4. A sewing machine according toclaim 2, further comprising a pivoting axle, said curved hook being fixed to said axle, said means for oscillating said curved hook comprising a main oscillating lever driven by said crankshaft, said oscillating lever being adapted to oscillate between an upper and a lower position, a lever attached to said axle and a rod connecting said main oscillating lever and said lever, the length of the connecting rod being such that the curved hook remains substantially stationary in the lower position thereof during the last part of the upward and the first part of the downward travel of the main oscillating lever.

5. A sewing machine according to claim 4 where the respective connection of the threaded hook and of the curved hook are such that said curved hook remains stationary when said threaded hook cooperates with said needle.

6. A sewing-machine according to claim 1 further comprising an oil-tight bearing in the top of the case,

.trimming means, said trimming means including a knife stationary part fixedly mounted above the work support, an endwise reciprocating knife mobile part extending up from within the case through said oil-tight bearing, and

connections within said case from said crankshaft for reciprocating said knife mobile part.

7. A sewing machine as claimed in claim 1, further comprising a feed dog-bearing bar, a bushing, a swivel set in said bushing, openings in said bushing to allow for the passage of said feed dog-bearing bar therethrough; said gearcase having a housing, said housing having said bushing therein and openings in said housing for the passage of the bar into the gearcase; said feed dog-bearing bar being slidingly mounted in said swivel and extending through said opening in said bushing and said housing into said gearcase; a feeding mechanism and a litting mechanism operatively connecting said feed dogbearing bar to said crankshaft.

8. A sewing machine as claimed in claim 1 further comprising thread distributor for the threaded hook which comprises a sector of U section, said sector comprising two tlanges and being adjustably fixed by one of said flanges to the gearcase, each of the flanges forming said sector having a hole therein for the passage of thread to the threaded hook, said holes being in alignment with each other, an axle controlled by the crankshaft to make a constant alternating rotary motion, a lever between the anges of said sector, one end of said lever being integral with said axle, the other end of said lever passing through an opening at the base of the U, said lever being adapted to engage thread passing through the holes in said flanges to pull the desired length of thread through said holes, the length of distributed thread being set by the position f said holes in relation with the gearcase.

9. A sewing machine according to claim 1 further comprising a feed dog and including openings in said case through which said hook bar and said oscillating means extend, oil-tight sealing means in said openings around said hook bar, said oscillating means and said feed dog means tightly sealing said case.

10. A sewing machine according to claim 2 in which said relatively rapid lift of the threaded hook brings said threaded end substantially to the same level as the work support.

l1. A sewing machine as claimed in claim 1 further comprising a knife having a stationary part and a mobile part, the latter part being operatively connected to be driven by said crankshaft to Amove upwardly from within said gearcase to cut the edge of objects to be overcast, a pressing pedal, a support mounting said pressing pedal and said stationary part of the knife on the case, said support being located near the needle bar, the upper surtace of said case presenting a substantially completely free working surface, the needle bar and the support being so located as to allow the overcasting of objects presenting any outline and particularly of objects presenting inner cuttings of a slight curve.

References Cited UNITED STATES PATENTS 2,363,774 1l/l944 Christensen et al. ll2-l62 X 3,101,686 S/l963 Hayes 112-162 3,145,672 8/1964 Marforio 112-162 954,025 4/ 1910 F irsching.

2,222,016 ll/ 1940 Becker 112--215 2,483,036 9/1949 Christensen ll2-2l5 XR JORDAN FRANKLIN, Primary Examiner.

JAMES R. BOLER, Assistant Examiner. 

